performance of 40 subjects on the single-leg triple hop (SLTH), with quadriceps (Quad 60,

Transcription

1 HAMILTON, ROBERT TYLER, M.S. Single-leg Triple Hop Test as a Predictor of Lower Limb Strength, Power, and Balance. (2006) Directed by Dr. Sandra J. Shultz. 77 pp. Problem: The extent to which single-leg hop tests are related to strength, power, and postural stability is unknown. Methods: A within-subjects design was used to compare performance of 40 subjects on the single-leg triple hop (SLTH), with quadriceps (Quad 60, Quad 180 ) and hamstrings (Ham 60, Ham 180 ) isokinetic strength at 60º s -1 and 180º s -1, vertical jump height (VJ), and scores on the Balance Error Scoring System test (BESS). During one session, subjects were tested on SLTH, VJ, and BESS. In a separate test session, strength was tested. Results: Individually, SLTH predicted 69.5% of the variance in VJ, and 49-59% in strength measures. No relationships were noted with BESS. Conclusions: The SLTH is a useful clinical test to predict an athlete s lower limb strength and power.

2 SINGLE-LEG TRIPLE HOP TEST AS A PREDICTOR OF LOWER LIMB STRENGTH, POWER, AND BALANCE by Robert Tyler Hamilton A Thesis Submitted to the Faculty of The Graduate School at The University of North Carolina at Greensboro in Partial Fulfillment of the Requirements for the Degree Master of Science Greensboro 2006 Approved by Sandra J. Shultz Committee Chair

3 APPROVAL PAGE This thesis has been approved by the following committee of the Faculty of The Graduate School at The University of North Carolina at Greensboro. Committee Chair Committee Members 07/20/06 Date of Acceptance by Committee 07/20/06 Date of Final Oral Examination ii

4 ACKNOWLEDGEMENTS I would like to gratefully acknowledge Sandy Shultz PhD, ATC, CSCS for her time and effort in advising me on this thesis. I would also like to thank David Perrin PhD, ATC and Randy Schmitz PhD, ATC for their service on my thesis committee. Additionally, I would like to thank Alan Donley MS, ATC, Janah Fletcher MS, ATC, Samantha McCoy, and Valerie Wolf MS, ATC for their assistance in data collection. iii

5 TABLE OF CONTENTS Page LIST OF TABLES... vi CHAPTER I. INTRODUCTION... 1 Statement of the Problem... 2 Objectives... 3 Assumptions and Delimitations... 4 Limitations... 4 Operational Definitions... 5 II. LITERATURE REVIEW... 7 Single-leg Triple Hop... 7 Summary III. METHODS Design Subjects Instrumentation Procedures Data Reduction Statistical Analyses IV. JOURNAL-FORMATTED MANUSCRIPT Abstract Introduction Methods Results Discussion References Tables REFERENCES APPENDIX A: RAW DATA iv

6 APPENDIX B: IRB FORM APPENDIX C: CONSENT FORM APPENDIX D: RESEARCH CONFIDENTIALITY FORM v

7 LIST OF TABLES Page TABLE 1. Mean ± Standard Deviation (SD) and Value Ranges for Single-leg Triple Hop (SLTH), Vertical Jump (VJ), BESS scores, and Quadriceps (Quad 60, Quad 180 ) and Hamstring (Ham 60, Ham 180 ) Peak Torque at 60 and 180 s Bi-variate Pearson Correlations for Single-leg Triple Hop (SLTH), Vertical Jump (VJ), Balance Error Scoring System (BESS), Quadriceps Peak Torque (Quad 60, Quad 180 ) at 60 and 180 s -1, Hamstrings Peak Torque (Ham 60, Ham 180 ) at 60 and 180 s Linear Regression: Single-leg Triple Hop (SLTH) Predicting Vertical Jump (VJ), Balance Error Scoring System (BESS), Quadriceps (Quad 60, Quad 180 ) and Hamstrings (Ham 60, Ham 180 ) Peak Torque at 60 and 180 s vi

8 CHAPTER I INTRODUCTION Single-leg hop tests were designed to assess functional performance in an injured extremity. (Daniel et al., 1982; Daniel, Stone, Riehl, & Moore, 1988; Barber, Noyes, Mangine, McCloskey, & Hartman, 1990; Noyes, Barber, & Mangine, 1991). These functional hop tests require muscular strength, neuromuscular coordination and joint stability in the lower limb (Daniel et al., 1982; Barber et al., 1990; Noyes et al., 1991), and are considered useful in the clinical setting because they require minimal equipment and time, and use the contralateral limb as a control (Daniel et al., 1988; Noyes et al., 1991; Ross, Langford, & Whelan, 2002). Designed to imitate the demands of sport and exercise, functional tests can be used by clinicians to determine an individual s readiness for return-to-play following injury or illness. Researchers initially utilized hop tests in the evaluation of post-surgical knee patients, specifically anterior cruciate ligamentreconstructed (ACL-r) patients, and determined the hop test s validity as an objective clinical measure (Daniel et al., 1982; Daniel et al., 1988). In healthy populations, functional tests may be used to detect abnormal limb symmetry or weakness (Ostenberg, E. Roos, Ekdahl, & H. Roos, 1998). Daniel et al. (1982) described bilateral performance on a single-leg hop test in subjects using a hop index. This limb symmetry index (LSI) (Barber et al., 1990) is an 1

9 objective tool that may be used in both injured (Daniel et al, 1982; Daniel et al, 1988; Noyes et al, 1991; Petschnig et al, 1998) and healthy (Daniel et al, 1982; Daniel et al, 1988; Ostenberg et al, 1998) populations for the purpose of identifying strength and functional imbalances, and is determined by the ratio of performance of the weaker limb (e.g. injured or non-dominant) to the performance on the stronger limb (e.g. uninjured or dominant), multiplied by 100. Noyes et al (1989) determined an LSI of 85% or greater as being within a normal range of symmetry for both males and females. But while single-leg hop tests can be measured objectively and have been shown to be valid and reliable (Barber et al., 1990; Noyes et al., 1991; Bolgla & Keskula, 1997; Ross et al., 2002), the clinical implications of performance deficits are not well understood. Noyes and others (1991) tested anterior cruciate ligament-deficient (ACL-d) subjects on four hop tests, and found 52% of subjects were unable to perform satisfactorily on a single-leg hop test. However, they concluded that the tests were not able to detect the subject s specific functional limitations. That is, although limb asymmetries were noted, investigators were unable, from their study design, to determine the primary cause of abnormal function in injured subjects (e.g. strength or balance deficits). Statement of the Problem Although hop tests are reported to test components of strength, power and balance, the extent to which deficits on a single-leg hop test correlate with any of these parameters has not been thoroughly investigated. Understanding these relationships would improve 2

10 the clinical usefulness of the SLTH in detecting imbalances and deficits in preseason screening and following injury. Therefore, the purpose of this study was to determine the extent to which the SLTH test predicted performance on measures of strength, power and balance. Specifically, the intent was to examine whether the single-leg triple hop-fordistance was related to isokinetic quadriceps and hamstring strength, vertical jump height and BESS scores. Objectives 1. The first objective is to demonstrate that SLTH distance predicts performance on individual measures of strength, power and balance. Hypothesis 1: Single-leg triple hop distance will positively predict isokinetic strength of the quadriceps and hamstrings at 60 and 180º/sec. Hypothesis 2: Single-leg triple hop distance will positively predict vertical jump height. Hypothesis 3: Single-leg triple hop distance will negatively predict performance on the Balance Error Scoring System (BESS) test. 2. The second objective was to demonstrate that clinical measures of strength, power and balance will collectively predict performance on a SLTH. Hypothesis 4: Greater isokinetic leg strength and vertical jump height and lower BESS scores will combine to predict greater single-leg triple hop distance. 3

11 Assumptions and Delimitations 1. Subjects wore self-selected footwear for the SLTH and vertical jump test, and were barefoot for the BESS test. It was assumed that the difference in footwear will not affect the relationship between variables within each subject. 2. Isokinetic testing took place after the beginning of the competitive pre-season. It is assumed that minimal strength gains occurred between pre-season screening and strength measurements. 3. Only the dominant leg (defined as the stance leg when kicking a ball) was tested for the BESS test. Thus, all comparisons were limited to the dominant limb. 4. Only female and male college-aged soccer players were studied. The age range was limited to The BESS test is a reliable and valid measure of balance (Reimann, Guskiewicz, & Shields, 1999; Guskiewicz, Ross, & Marshall, 2001). 6. The vertical jump test is a reliable and valid measure of leg power (Markovic, Dizdar, Jukic, & Cardinale, 2004). Limitations 1. Different examiners conducted each of the tests examined in this study. However, measures for each individual test were measured by the same examiner for SLTH, isokinetic strength and power testing. BESS tests were conducted by two examiners. 4

12 2. Subjects followed a station-to-station format, with the starting station randomly assigned. Subjects also participated in several other exertional tests during the stationto-station preseason testing. Thus, the testing order was not strictly controlled. 3. Results may not be generalized to populations other than healthy, active college-aged soccer athletes. Operational Definitions Functional Test Any of a number of clinical tests used to assess an individual s ability to participate in sport-specific activities. Single-leg Triple Hop-for-Distance Test A functional hop test where the athlete begins on a single leg, and performs three consecutive maximal hops forward. The test is scored as the total distance covered from the starting line to the subject s heel contact on the final hop. Isokinetic Quadriceps Strength The greatest peak torque produced during concentric knee extension at fixed angular velocities of 60º/sec. and 180º/sec., as measured by the Biodex TM System 3 Pro dynamometer. Isokinetic Hamstring Strength The greatest peak torque produced during concentric knee flexion at fixed angular velocities of 60º/sec. and 180º/sec., as measured by the Biodex TM System 3 Pro dynamometer. Average Torque (Nm) The greatest peak torque obtained from one of five maximal effort test repetitions achieved during an isokinetic strength test. 5

13 Vertical Jump A functional test of lower limb power in which an individual performs a countermovement jump (CMJ) to achieve maximal vertical height. The test is scored as the difference (in centimeters) between a subject s stand-and-reach height and jump-andreach height as measured by the Jump It measurement system. Balance Error Scoring System A static balance test of six stance conditions on two surfaces, scored by assigning a point for each specific postural error. Balance Error Score The cumulative number of errors a subject commits over 6 static stance conditions based on a scoring system developed by Riemann et al. (1999). One error point is given for each error committed. 6

14 CHAPTER II LITERATURE REVIEW This review will focus on the single-leg triple hop-for-distance, and research that has examined its relationship with measures of strength, power and balance to provide a foundation for the current study. Single-leg Triple Hop The single-leg triple hop (SLTH) test is one of four functional tests described by Noyes et al. (1991). It is performed by standing behind a start line on a designated testing leg, and begins with an individual s ability to generate initial movement. The subject takes three consecutive maximal hops forward and lands on the same testing leg each time. The SLTH is measured in total distance from the start line to the point of heel contact after the third consecutive hop. As with other single-leg tests presented by Noyes and colleagues (1991), the SLTH test requires the subject to move horizontally over a distance, thus requiring the generation of forward momentum and postural stability to achieve a successful result. Hence, the theoretical purpose of the SLTH is to test an individual s strength, power and kinesthesia (Ross et al., 2002). Research has shown that both the single-leg hop and SLTH are reliable measures of lower extremity performance 7

15 in healthy subjects (ICC =.95; SEM = cm) (Bolgla & Keskula, 1997), and correlate well with one another (r =.77; P<.001) (Ostenberg et al., 1998). These findings suggest that the two tests may be used interchangeably, and therefore findings related to both tests will be covered in this review. Relationship of SLTH with Strength, Power and Balance Clinicians often utilize several objective measures in a lower extremity rehabilitation program to measure improvements in strength, power and balance to determine an individual s readiness for progression to a new phase. The following will discuss the purposes of these tests, and what we know about their relationship with the single-leg triple hop-for-distance. Isokinetic Testing Isokinetic strength testing is commonly used in clinical practice for tracking progress and determining functional readiness during rehabilitation. Among lower limb uses, isokinetic testing is most commonly used in knee injury rehabilitation programs. Resulting data offer insight into an individual s overall strength, power or endurance (Perrin, 1993). Debate continues in the literature on the issue of which specific measures to use in expressing isokinetic strength. Peak torque (PT) is commonly used in reporting strength (Daniel et al., 1982; Wilk, Romaniello, Soscia, Arrigo, & Andrews, 1994; Greenberger & Paterno, 1995; Pincivero, Lephart, & Karunakara, 1997; Ostenberg et al., 1998; Petschnig, 8

16 Baron, & Albrecht, 1998; Mattacola et al., 2002). It represents the greatest torque produced in a range of motion. Relationship to hop tests. Several studies demonstrated a positive relationship between performance on a single-leg hop test and isokinetic strength (Barber et al., 1990; Noyes et al., 1991; Wilk et al., 1994). Research has shown that the LSI for strength measures correlates well with LSI on a single-leg hop test. In a study of healthy and ACL-d subjects, Barber and colleagues (1990) found that of 18 abnormal LSI on an isokinetic strength test, 12 also had abnormal LSI on a single-leg hop for distance. Other research has shown moderate relationships between strength measures and hop tests. In a study of 67 ACL-d patients, Noyes et al. (1991) performed a linear regression analysis on a single-leg hop and 60 /sec. isokinetic strength tests. Moderate but statistically significant relationships were noted for quadriceps strength (r= 0.49, P< ) and hamstrings strength (r= 0.32, P< 0.02) with the single-leg hop. Wilk and others (1994) also found a correlation between isokinetic testing (180 /sec.) and three single-leg hop tests (r= 0.62, P< 0.003). While the literature suggests that single-leg hop tests may confirm functional limitations, their ability to identify specific deficiencies is unclear (Barber et al., 1990; Noyes et al., 1991). That is, whether poor performance on a singleleg hop test is simply due to lower limb strength deficits or may also be affected by inadequate balance or power remains to be determined. 9

17 Lower Limb Power The maximal vertical jump is commonly used as a test of lower limb power. Toumi, Best, Martin, F Guyer, & Poumarat (2004) reported the vertical jump requires a combination of force, power and muscle synchronization during the stretch-shortening cycle. Furthermore, they conjectured specific neuromuscular adaptations may lead to improved work necessary for vertical jump performance. Questions remain as to the particular nature of the neuromuscular coordination required. In spite of this, lower limb power is essential to successful performance of this task (Markovic et al., 2004). Two types of vertical jump tests commonly appear in the research literature the squat jump (SJ) and countermovement jump (CMJ). Both were recently reported as the most reliable (α= 0.97 and 0.98, respectively) and valid field tests for the estimation of lower limb power in active men (Markovic et al., 2004). The investigators randomly assigned ninety-three healthy subjects to four groups. Each group was randomly tested on seven vertical and horizontal jumps on four occasions. SJ and CMJ had the best factorial validity as well as reliability among the jumps. The authors noted the SJ and CMJ allow the investigator the possibility of studying contractile characteristics and effect of prestretch on explosive power. They concluded a CMJ using a contact mat with digital timer provided the highest factorial validity of numerous vertical jump tests. Relationship to hop tests. To achieve maximum distance on the SLTH, rapid deceleration and acceleration or muscular power -- is required upon ground contact. 10

18 The vertical jump is considered an index of muscle power, and may be used as part of a battery of performance tests (Gustavsson et al., 2006). Limited studies have examined the relationship between the vertical jump, as a measure of power, and horizontal hop tests. Gustavsson and others (2006) recently compared healthy subjects (n=15), ACLreconstructed subjects six months following reconstruction (n=35), and ACLreconstructed subjects eleven months post-reconstruction (n=30) on a battery of functional tests. Strong correlations were found in the three-test battery, which included single-leg vertical jump and single-leg hop for distance (r s = 0.70 to 0.94, p = 0.01). Specificity (the percentage probability that the tests would demonstrate a normal LSI in the normal subjects) of vertical jump and hop for distance was reported as 87% and 100%, respectively. Therefore, healthy subjects performed normally between limbs on the vertical jump 87% of the time. Likewise, healthy subjects performed normally on the hop-for-distance 100% of the time. Given the strong relationship between the single-leg hop-for-distance and the single-leg triple hop-for-distance (Ostenberg et al., 1998), these data would suggest that performance on the single-leg triple hop-for-distance may correlate well with vertical jump height and be predictive of lower limb power. 11

19 Balance Balance is a complex and continuous interaction between the body s neuromuscular system and the surrounding environment (Nashner, 1993). Healthy individuals utilize the visual, vestibular, and somatosensory systems to maintain upright posture in the presence of gravity and other environmental stimuli (Guskiewicz & Perrin, 1996). Additionally, motor coordination is required to make postural adjustments during a task (Horak, 1987; Guskiewicz & Perrin, 1996). These factors help determine success in specific tasks that require control of upright posture during sport activity. Postural stability may be objectively measured using a forceplate, the NeuroCom EquiTest, or a clinical measure such as the Balance Error Scoring System (BESS). Riemann and colleagues (1999) introduced the BESS as a reliable and valid (Guskiewicz et al., 2001) measure of balance that can be performed in the clinical setting. The BESS has primarily been studied for administration as a clinical test for detecting effects of mild head injury (Riemann & Guskiewicz, 2000; Guskiewicz et al., 2001; Valovich, Perrin, & Gansneder, 2003; Wilkins, Valovich McLeod, Perrin, & Gansneder, 2004; Susco, Valovich McLeod, Gansneder, & Shultz, 2004). However, investigators have recently compared BESS scores in 30 healthy subjects and 30 subjects with functional ankle instability (FAI), and concluded the BESS is also sensitive enough to detect FAI (Docherty, Valovich McLeod, & Shultz, 2006). Group differences were noted in total balance error scores, as well as 3 of the 6 stance conditions. Therefore, the BESS may be useful in detecting functional performance deficits. 12

20 The BESS uses three stance conditions (double leg, single leg and tandem stances) on two surfaces (stable and unstable) to objectively measure balance, and indicates an individual s ability to coordinate sensory input in a static stance. During each stance condition, errors are recorded for each of the following: 1) lifting hands off iliac crests; 2) opening eyes; 3) stepping, stumbling, or falling; 4) remaining out of the test position for more than 5 seconds; 5) moving hip into more than 30º of flexion or abduction; 6) lifting forefoot or heel (Riemann et al., 1999). Higher BESS scores have been identified in subjects following mild head injury (Guskiewicz et al., 2001) and in subjects with FAI (Docherty et al., 2006). Relationship to hop tests. When performing the SLTH, postural control is required to maintain a straight heading. Theoretically, balance during a functional movement requires sensory and motor coordination of lower limb joints. Several studies have recently examined postural stability at the completion of a dynamic task (Ross & Guskiewicz, 2004; Wikstrom, Powers, & Tillman, 2004; Wikstrom, Tillman, & Borsa, 2005; Wikstrom, Tillman, Smith, & Borsa, 2005), as a predictor of injury (McGuine, Greene, Best, & Leverson, 2000), as a function of foot structure (Hertel, Gay, & Denegar, 2002; Cote, Brunet, Gansneder, & Shultz, 2005), and following ACL-reconstruction (Mattacola et al., 2002), suggesting a relationship between static balance performance and functional ability. However, no studies were found examining the relationship between a static balance test and a functional hop test in healthy subjects. 13

21 Mattacola and colleagues (2002) studied several clinical measures in ACLreconstructed patients compared with age and activity-matched healthy controls. They observed significant differences between groups on the single-leg hop-for-distance in the involved limb (P< 0.05), but no significant differences in single-leg or double-leg dynamic postural stability measured on Biodex TM Stability System. However, the investigators did not compare within-subjects measures for potential relationships between these variables. A comprehensive search of the literature revealed no studies using a SLTH as a predictor of performance on a static balance test in healthy subjects. Summary Tests of strength and balance are commonly conducted in rehabilitation settings to determine an individual s readiness for progression to functional activities. Functional hop tests like the single-leg triple hop test are thought to require a combination of muscular strength, power and balance for task execution. However, the extent to which the single-leg triple hop accurately relates to or measures deficits in any of these components of performance (muscular strength, power and balance) has not been quantified. Understanding these relationships would improve the clinical usefulness of the SLTH in detecting imbalances and deficits in preseason screening and following injury. Therefore, the purpose of this study is to examine if the single-leg triple hop test can predict performance on tests of lower limb muscular strength, lower limb power and balance. 14

22 CHAPTER III METHODS Design A within-subjects retrospective design was used to compare performance on the SLTH, with isokinetic strength of the quadriceps and hamstring muscles, vertical jump height and scores on the BESS. During a station-to-station pre-season screening, subjects were tested on the SLTH and vertical jump with shoes on, and the BESS with shoes and socks removed. In a separate test session, subjects performed an isokinetic strength test (knee flexion/extension; concentric/concentric) consisting of one set of five test repetitions at each of two angular velocities (60º/sec and 180º/sec). The independent (predictor) variable was the maximum distance covered (cm) from the toe at the starting line to heel contact upon the final hop during the SLTH. The dependent variables were peak torque (Nm) for the quadriceps and hamstrings at 60º/sec (Quad 60, Ham 60 ) and 180º /sec (Quad 180, Ham 180 ), maximal vertical jump height (VJ) (cm) and balance error score. Subjects 40 NCAA Division IAA Men s and Women s Soccer student-athletes, ranging in age from participated (20 females, 20 males, 20.0 ± 1.4 years, ± 9.2 cm, 71.9 ± 8.9 kg). Inclusion criteria were: active status on the Men s or Women s Soccer roster, completion of the pre-participation physical examination, completion of all functional performance tests and clearance for participation. Exclusion criteria were absence from 15

23 any part of the pre-participation physical examination or an inability to complete any of the required four tests. All subjects gave informed consent to participate by signing a form approved by the University s Institutional Review Board. Instrumentation SLTH data was collected using a tape measure affixed to the ground. Isokinetic strength testing was performed using a Biodex TM System 3 Pro isokinetic dynamometer (Biodex Medical Systems, Shirley, NY), and data collected using Biodex TM software (Rev Beta; Biodex Medical Systems, Shirley, NY). Vertical jump height was collected using a Jump It measurement standard (Excel Sports Products, Costa Mesa, CA). The BESS test was conducted on a wood gymnasium floor and with a 2.5 inch thick AirEx balance pad (Alcan Airex AG, Sins, Switzerland), and timed with a stopwatch. Procedures Overview Subjects reported to either the Athletic Training Room (freshman and transfer students) or the 2-Court gymnasium (returning students) in the University of North Carolina at Greensboro s School of Health and Human Performance. After they provided their informed consent, subjects participated in a comprehensive pre-participation examination. Stations included a general medical screening, orthopedic screening, general joint laxity screening, lower limb anatomic alignment, sport psychology survey, 16

24 functional testing, static balance testing and kinematic analysis of landing. Athletes rotated through a total of 16 testing stations, with the starting station randomly assigned. Approximately five weeks later, each subject reported to the Athletic Training Room for isokinetic strength testing. During the interval between testing sessions, the subjects participated in soccer practice and games. They began participating in strength training between one and three weeks prior to the second testing session. Therefore, no significant strength gains were anticipated prior to strength testing. Data from the isokinetic strength testing, VJ, BESS, and SLTH were extracted for this study. The procedures for each test used in this study are described below. All tests were performed on the subjects dominant limb, defined as the preferred stance leg used when the subjects kicked a ball as far as possible. Single-leg Triple Hop Test A tape measure was fixed to the ground perpendicular to a starting line. Subjects stood on the designated testing leg, with their toe on the starting line. The subject took three consecutive maximal single-leg hops forward. The investigator measured the distance hopped, from the starting line to the point where the heel struck the ground upon completing the third hop. Arm swing was allowed. Subjects were given 1-3 practice trials and then completed three test trials. A test trial was repeated if the subject was unable to complete a triple hop without contacting the ground with the opposite leg. The maximum distance recorded from the three trials was used for analysis. Subjects wore self-selected athletic footwear during the test. 17

25 Balance Error Scoring System (BESS) The BESS comprises six conditions: double-leg, single-leg and tandem stances on both a firm surface and foam surface (Riemann et al., 1999). The foam surface consisted of a 2.5 inch thick, closed cell Airex balance pad (Alcan Airex AG, Sins, Switzerland). Each of the six conditions was performed for 20 seconds, with eyes closed. A stopwatch was used for timing, and testing was video recorded for scoring. Trials were performed facing a wall to minimize distraction. Balance errors were recorded during each testing condition as described by Riemann et al. (1999). One error was recorded for each of the following: 1) lifting hands off iliac crests; 2) opening eyes; 3) stepping, stumbling, or falling; 4) remaining out of the test position for more than 5 seconds; 5) moving hip into more than 30º of flexion or abduction; 6) lifting forefoot or heel. The total errors were then summed across the 6 conditions and used for analysis. Vertical Jump A countermovement jump (CMJ) was used to perform the vertical jump-andreach test. Subjects were tested wearing the same self-selected athletic footwear that was used in the SLTH. Testing began by standing beneath the Jump It measurement standard (Excel Sports Products, Costa Mesa, CA) with both feet flat on the ground, and reaching as high as possible. The Jump It consists of an aluminum standard on a fillable base, with spring pegs placed at one-inch increments. First, stand-and-reach height was recorded. Next, the subjects were instructed to jump as high as possible and contact the 18

26 highest peg they could reach on the Jump-It measurement standard. Jump-and-reach height was recorded, and jump height was calculated by subtracting the stand-and-reach height from the jump-and-reach height. During the countermovement jump, arm swing was allowed, but an approach step was not permitted. Subjects were permitted 1-3 practice jumps prior to completing three test trials. The maximum height from the three test trials was used for analysis. Isokinetic Strength Testing Isokinetic strength testing was performed on a Biodex TM System 3 Pro (Biodex Medical Systems, Shirley, NY) at angular velocities of 60 /second and 180 /second using a protocol established for all University student-athletes. The subjects were tested for concentric knee extension and flexion in a seated position, with hip and thigh stabilization straps applied. The seat angle was set at 85º and the knee angle was 90º. The knee axis of rotation was aligned with the dynamometer shaft. The bottom of the resistance pad was placed just superior to the medial malleolus and was secured with the stabilization strap. Range of motion (ROM) stops were set at 90º flexion and 18º extension for a total ROM of 72º. Gravity correction was performed. Subjects warmed up on a cycle ergometer for 5-10 minutes, followed by a selfdirected quadriceps and hamstrings stretching. Following set-up on the Biodex TM, the subjects were always tested on the dominant limb first. Prior to testing, all subjects completed a standardized familiarization protocol that consisted of four consecutive increasing efforts. Subjects were instructed to perform the first repetition at 25% of 19

27 maximal effort, the second repetition at 50% of maximal effort, the third repetition at 75% effort and the fourth repetition at maximal effort. Once this familiarization protocol was completed, five maximal effort test repetitions were performed at 60 /sec. During the test repetitions, verbal encouragement was given to apply force as hard and as fast as possible for both knee extension and flexion, on every repetition. The subject was then given a ten-second recovery, whereupon the familiarization and testing repetitions were performed at 180 /sec. The non-dominant limb was then tested using the same procedures. Following completion of the testing, subjects cooled down on the cycle ergometer. Data Reduction Isokinetic Quadriceps and Hamstrings Strength (dependent variables) Isokinetic quadriceps and hamstrings strength measures were recorded and calculated using Biodex TM software Rev Beta (Biodex Medical Systems, Shirley, NY). Isokinetic quadriceps and hamstrings strength was calculated by extracting the respective test repetitions at each angular velocity (60º/sec. and 180º/sec.) with the highest peak torque across the entire range of motion (Nm). 20

28 Vertical Jump Height (dependent variable) Vertical jump-and-reach heights were visually taken by observing the highest spring peg reached by the subject. Heights (cm) were recorded on a scoring sheet, and the stand-and-reach height was subtracted from the maximum jump-and-reach height. The maximum vertical jump height was then extracted for data analysis. Balance Error Score (dependent variable) BESS tests were video recorded and observed for balance error scores as described previously (Riemann et al., 1999). The subject s total error score was recorded on their scoring sheet and used for data analysis. Single-leg Triple Hop (independent variable) SLTH distance was visually recorded using a tape measure to the nearest centimeter (cm). Maximum hop distance across the three trials was used for data analysis. Statistical Analyses Descriptive data (means, standard deviations and range values) were recorded for each variable. To examine the first objective, relationships between SLTH and each of the variables (Quad 60, Quad 180, Ham 60, Ham 180, BESS scores, and VJ height) were analyzed using single linear regression models and bi-variate Pearson correlation coefficients. Alpha level for all analyses was set at P <

29 CHAPTER IV JOURNAL-FORMATTED MANUSCRIPT Single-leg Triple Hop is a Valid Test of Lower Limb Strength and Power R. Tyler Hamilton, MS, ATC hamiltonrt@aol.com Sandra J. Shultz, PhD, ATC, CSCS sjshultz@uncg.edu Randy J. Schmitz, PhD, ATC rjschmit@uncg.edu David H. Perrin, PhD, ATC dhperrin@uncg.edu Department of Exercise and Sport Science The University of North Carolina at Greensboro Address correspondence to Sandra J. Shultz PhD, ATC, CSCS, The University of North Carolina at Greensboro, 237B HHP Building, P.O. Box 26170, Greensboro, NC Address to sjshultz@uncg.edu. 22

30 Abstract Single-leg Triple Hop is a Valid Test of Lower Limb Strength and Power Context: Single-leg hop tests are functional tests which reportedly require strength, power, and postural stability to perform. The extent to which a single-leg hop test requires each of these characteristics is unknown. Objective: To assess the extent to which a single-leg triple hop test predicts performance on clinical tests of power, strength, and balance in athletic individuals. Design: Within-subjects retrospective design. Setting: Preseason athlete screening. Patients or Other Participants: 40 NCAA Division IAA Men s and Women s Soccer student-athletes (20 females, 20 males, 20.0 ± 1.4 years, ± 9.2 cm, 71.9 ± 8.9 kg). Main Outcome Measure(s): Single-leg triple hop (SLTH), vertical jump (VJ), Balance Error Scoring System(BESS), quadriceps (Quad 60, Quad 180 ) and hamstrings (Ham 60, Ham 180 ) isokinetic strength at 60 and 180 s -1 were measured as part of a comprehensive preseason athletic screening. Results: SLTH was a strong predictor of VJ height, explaining 69.5% of the variance (p<0.0001). SLTH predicted 56.7% of the variance in Ham 60 (p<0.0001) and 55.5% of the variance on Ham 180 (p<0.0001). SLTH predicted 49% of the variance in Quad 60 (p<0.0001) and 58.8% of the variance in Quad 180 (p<0.0001). Conclusions: Our subjects demonstrated that the SLTH is a useful clinical test to predict an athlete s strength and power. However, further study into postural stability is required to perform a SLTH is warranted. 23

31 1 Key Words: functional test, peak torque, balance, postural stability, open-kinetic chain 24

32 1 2 INTRODUCTION Single-leg hop tests were designed to assess functional performance in an injured 3 extremity. 1-4 These functional hop tests require muscular strength, neuromuscular 4 5 coordination and joint stability in the lower limb, 1,3,4 and are considered useful in the clinical setting because they require minimal equipment and time, and use the 6 contralateral limb as a control. 2,4,5 Designed to imitate the demands of sport and exercise, functional tests can be used by clinicians to determine an individual s readiness for return-to-play following injury or illness. Researchers initially utilized hop tests in the evaluation of post-surgical knee patients, specifically anterior cruciate ligamentreconstructed (ACL-r) patients, and determined the hop test s validity as an objective 11 clinical measure. 1,2 In healthy populations, functional tests may be used to detect abnormal limb symmetry or weakness. 6 But while single-leg hop tests can be measured objectively and have been shown to be reliable, 3-5,7 the clinical implications of performance deficits are not well understood. Noyes and others 4 tested anterior cruciate ligament-deficient (ACL-d) subjects on four hop tests, and found 52% of subjects had abnormal limb symmetry during a single-leg hop test. However, they concluded that the tests were not able to detect the subject s specific functional limitations. That is, although limb asymmetries were noted, investigators were unable, from their study design, to determine the primary cause of abnormal function in injured subjects (e.g. strength or balance deficits). Although hop tests are reported to test components of strength, power and balance, the extent to which deficits on a single-leg hop test correlate with any of these parameters 25

33 has not been thoroughly investigated. Understanding these relationships would improve the clinical usefulness of the SLTH in detecting imbalances and deficits in preseason screening and following injury. Therefore, our purpose was to determine the validity of the SLTH test as a predictor of performance on measures of strength, power and balance. Specifically, our intent was to examine whether the single-leg triple hop-for-distance is related to isokinetic quadriceps and hamstring strength, vertical jump height and BESS scores METHODS Design We used a within-subjects retrospective design to compare performance on the single-leg triple hop-for-distance test (SLTH), with isokinetic strength of the quadriceps and hamstring muscles, vertical jump height, and scores on the Balance Error Scoring System test (BESS). During a station-to-station pre-season screening, we tested subjects on the SLTH and vertical jump with shoes on, and the BESS with shoes and socks removed. In a separate test session, subjects performed an isokinetic strength test (knee flexion/extension; concentric/concentric) consisting of one set of five test repetitions at each of two angular velocities (60º s -1 and 180º s -1 ). The independent (predictor) variable was the maximum distance covered (cm) from the toe at the starting line to heel contact upon the final hop during the SLTH. The dependent variables were average torque (Nm) for the quadriceps (Quad 60, Quad 180 ) and hamstrings (Ham 60, Ham 180 ) at 60º s -1 and 180º s -1, maximal vertical jump height (VJ) (cm), and BESS score. 26

34 Subjects Forty NCAA Division IAA Men s and Women s Soccer student-athletes, ranging in age from participated (20 females, 20 males, 20 ± 1.4 years, ± 9.2 cm, 71.9 ± 8.9 kg). Inclusion criteria were: active status on the Men s or Women s Soccer roster, completion of the pre-participation physical examination, completion of all functional performance tests and clearance for participation. Exclusion criteria were absence from any part of the pre-participation physical examination or an inability to complete any of the required four tests. All subjects gave informed consent to participate by signing a form approved by the University s Institutional Review Board Instrumentation We collected SLTH data using a tape measure affixed to the ground. We performed isokinetic strength testing using a Biodex TM System 3 Pro isokinetic dynamometer (Biodex Medical Systems, Shirley, NY), and data collection using Biodex TM software (Rev Beta; Biodex Medical Systems, Shirley, NY). We collected VJ height using a Jump It measurement standard (Excel Sports Products, Costa Mesa, CA). We conducted the BESS test on a wood gymnasium floor and with a 2.5 inch thick AirEx balance pad (Alcan Airex AG, Sins, Switzerland), and timed with a stopwatch

35 Procedures Overview. After providing their informed consent, subjects participated in a comprehensive pre-participation examination. Stations included a general medical screening, orthopedic screening, general joint laxity screening, lower limb anatomic alignment, sport psychology survey, functional testing, static balance testing and kinematic analysis of landing. Athletes rotated through a total of 16 testing stations, with the starting station randomly assigned. Approximately five weeks later, each subject reported to the Athletic Training Room for isokinetic strength testing. During the interval between testing sessions, the subjects participated in soccer practice and games. They began participating in strength training between one and three weeks prior to the second testing session. Therefore, minimal strength gains may have occurred during this interval. We extracted data from the isokinetic strength testing, vertical jump, BESS, and SLTH for our study. The procedures for each test used in this study are described below. We performed all tests on the subjects dominant limb, defined as the preferred stance leg used when the subjects kick a ball as far as possible Single-leg Triple Hop Test. We fixed a tape measure to the ground perpendicular to a starting line. Subjects stood on the designated testing leg, with their toe on the starting line. The subject took three consecutive maximal single-leg hops forward. The investigator measured the distance hopped, from the starting line to the 21 point where the heel struck the ground upon completing the third hop. 7 Arm swing was 22 allowed. Subjects were given 1-3 practice trials and then completed three test trials. A 28

36 test trial was repeated if the subject was unable to complete a triple hop without contacting the ground with the opposite leg. The maximum distance recorded from the three trials was used for analysis. Subjects wore self-selected athletic footwear during the test. 5 6 Balance Error Scoring System (BESS). The BESS comprises six conditions: 7 double-leg, single-leg and tandem stances on both a firm surface and foam surface. 8 The foam surface consisted of a 2.5 inch thick, closed cell Airex balance pad (Alcan Airex AG, Sins, Switzerland). Each of the six conditions was performed for 20 seconds, with eyes closed. A stopwatch was used for timing, and testing was video recorded for scoring. Subjects performed trials facing a wall to minimize distraction. We recorded 12 balance errors during each testing condition as described by Riemann et al. 8 We recorded one error for each of the following: 1) lifting hands off iliac crests; 2) opening eyes; 3) stepping, stumbling, or falling; 4) remaining out of the test position for more than 5 seconds; 5) moving the hip into more than 30º of flexion or abduction; 6) lifting the forefoot or heel. We then summed the total errors across the 6 conditions and used the total score for analysis Vertical Jump. Subjects performed a countermovement jump for the VJ. Subjects were tested wearing the same self-selected athletic footwear that were used in the SLTH. Testing began by standing beneath the Jump It measurement standard (Excel Sports Products, Costa Mesa, CA) with both feet flat on the ground, and reaching 29

37 as high as possible. The Jump It consists of an aluminum standard on a fillable base, with spring pegs placed at one-inch increments. First, stand-and-reach height was recorded. Next, we instructed subjects to jump as high as possible and contact the highest peg they could reach on the Jump-It measurement standard. Jump-and-reach height was then recorded, and jump height was calculated by subtracting the stand-andreach height from the jump-and-reach height. During the countermovement jump, arm swing was allowed, but an approach step was not permitted. Subjects were permitted 1-3 practice jumps prior to completing three test trials. Maximum height from the three test trials was used for analysis Isokinetic Strength Testing. Isokinetic strength testing was performed on a Biodex TM System 3 Pro (Biodex Medical Systems, Shirley, NY) at angular velocities of 60 s -1 and 180 s -1 using a university-specific protocol. Subjects were tested for concentric knee extension and flexion in a seated position, with hip and thigh stabilization straps applied. Seat angle was set at 85º and the knee angle at 90º. The knee axis of rotation was aligned with the dynamometer shaft. The bottom of the resistance pad was placed just superior to the medial malleolus and secured it with the stabilization strap. Range of motion (ROM) stops were set at 90º flexion and 18º extension for a total ROM of 72º, and gravity correction was performed. Subjects warmed up on a cycle ergometer for 5-10 minutes, followed by selfdirected quadriceps and hamstrings stretching. Following set-up on the Biodex TM, the non-dominant limb was tested first. Prior to testing, all subjects completed a 30

38 standardized familiarization protocol that consisted of four consecutive increasing efforts. Subjects were instructed to perform the first repetition at 25% of maximal effort, the second repetition at 50% of maximal effort, the third repetition at 75% effort and the fourth repetition at maximal effort. Once subjects completed this familiarization protocol, they performed five test repetitions at 60 s -1. During the test repetitions, we gave verbal encouragement to apply force as hard and as fast as possible for both knee extension and flexion, on every repetition. The subject was then given a ten-second recovery, whereupon they performed familiarization and testing repetitions at 180 s -1. We then tested the dominant limb using the same procedures. Following completion of the testing, subjects cooled down on the cycle ergometer

39 Data Reduction Isokinetic Quadriceps and Hamstrings Strength (dependent variables). We recorded and calculated isokinetic quadriceps and hamstrings strength measures through Biodex TM software Rev Beta (Biodex Medical Systems, Shirley, NY). We calculated Quad 60, Quad 180, Ham 60, and Ham 180 by extracting the respective test repetitions at each angular velocity (60º s -1. and 180º s -1 ) with the highest peak torque (Nm). Vertical Jump Height (dependent variable). We visually took vertical jumpand-reach heights by observing the highest spring peg reached by the subject. We recorded heights on a scoring sheet, and subtracted the stand-and-reach height from the maximum jump-and-reach height. We then extracted the maximum vertical jump height (cm) for data analysis. Balance Error Score (dependent variable). We observed for balance error scores as described previously. 8 used for data analysis. The subject s total error score on their scoring sheet was Single-leg Triple Hop (independent variable). We visually recorded SLTH distance using a tape measure observed to the nearest centimeter (cm). The maximum hop distance across the three trials was used for data analysis

40 Statistical Analyses We recorded descriptive data (means, standard deviations and range values) for each variable. We analyzed individual relationships between SLTH and each of the variables (Quad60, Quad180, Ham60, and Ham180, BESS, and VJ) by examining bivariate Pearson correlation coefficients and single linear regression models. We set alpha level for all analyses at P < RESULTS Table 1 provides the descriptive statistics for SLTH, VJ, BESS, Quad 60, Quad 180, Ham 60, and Ham 180. Table 2 lists the bivariate Pearson correlations comparing each of the strength, power and balance measures to SLTH. Table 3 presents the linear regression summary results when predicting each of the dependent variables from the subject s performance on the SLTH. We noted significant correlations between the SLTH and VJ (R= 0.834; P<.01), Quad 60 (R=.700; P<.01), Quad 180 (R=.767; P<.01), Ham 60 (R=.753; P<.01), and Ham 180 (R=.745; P<.01), but we noted no significant correlation between SLTH and BESS score (R=.024; P<.01). SLTH was a strong predictor of VJ height, explaining 69.5% of the variance (p= ) (Table 3). These findings yielded a prediction equation of Y VJ = X SLTH, with greater SLTH distance predicting greater VJ height. The SLTH was also a strong predictor of quadriceps and hamstring strength at both 60 and 180 o s -1. SLTH predicted 49% of the variance in Quad 60 (p= ) and 58.8% of the variance in Quad 180 (p= ) (Table 3). The respective prediction equations for these 33

41 relationships were Y Q60 = X SLTH and Y Q180 = X SLTH. Similar relationships were noted when predicting hamstring strength from the SLTH, with the SLTH predicting 56.7% of the variance in Ham 60 (p= ) and 55.5% of the variance on Ham 180 (p= ) (Table 3). The respective prediction equations for these relationships were Y H60 = X SLTH and Y H180 = X SLTH. SLTH was not a significant predictor of performance on the BESS (Table 3) DISCUSSION The primary findings of this study were that that the SLTH was a positive predictor of performance on clinical power and strength tests. These findings suggest that a SLTH is a valid test of lower limb power and strength in NCAA Division I soccer players. However, we found no relationship between SLTH and BESS. When considered collectively, VJ had the strongest relationship with SLTH, followed by quadriceps strength at 180 s -1. However, single linear regression results suggest that SLTH would be a strong predictor of both quadriceps and hamstrings strength at either 60 s -1 or 180 s -1 when considered independently Power Single-leg hop-for-distance tests and vertical jump tests are both considered functional tests, and are reported in the literature to be useful as part of a battery of tests 21 to determine readiness to participate in activity. 9 However, to our knowledge, no 22 previous study has examined the validity of a SLTH as a predictor of a countermovement 34

42 1 jump. The VJ requires lower limb power in order to achieve maximal height. 10 That is, just as the VJ is dependent upon power applied vertically, the SLTH requires power generate horizontal distance. In spite of the difference in direction between a SLTH and VJ, one may infer that similar muscle activity occurs to produce extension at the hip, knee and ankle joints. Gustavsson and colleagues 9 determined that a single-leg vertical jump test and single-leg hop-for-distance test were highly correlated (r s = 0.70 to 0.94, P = 0.01). The data further suggests that SLTH and VJ provide similar results in 8 determining performance deficits. 11 Given the close relationship between a single-leg hop test and SLTH, 6 it is not surprising that performance on a SLTH predicts performance on a VJ. The results of the current study suggest that the SLTH may be considered a valid test of lower limb power Strength Previous studies have examined the relationship between performance on a 15 single-leg hop test and lower limb strength tests. 3,4,12 However, no studies were found which investigated the validity of a SLTH as a predictor of lower limb strength. In the current study, SLTH distance was a strong predictor of quadriceps and hamstrings strength as measured isokinetically. The strong relationship between SLTH and strength at both angular velocities suggests that either may be used in clinical practice. However, due to less torque placed on a joint, 180 s -1 may be more comfortable for a patient in rehabilitation. 35

43 Many activities require a combination of open-kinetic chain (OKC) and closedkinetic chain (CKC) strength. Soccer is a sport which clearly involves both types of strength to perform various multi-directional movements as well as kicking a ball. The strong correlation between isokinetic testing and the SLTH in the current study demonstrates the relationship between OKC and CKC strength. Comparisons to studies previously cited in the literature are somewhat difficult due to differences in protocols, investigators and angular velocities tested. Previous studies demonstrate a relationship between isokinetic quadriceps strength at numerous 9 angular velocities and single-leg hop tests. 3,4,12 However, no studies were found which examined the ability of performance on a SLTH to predict performance on isokinetic strength measures. The current study tested subjects at 60 and 180 s -1. Interestingly, bivariate Pearson correlation coefficients and regression results were similar for both quadriceps and hamstrings at 60 and 180º s -1. These results suggest that the SLTH may be used clinically to predict lower limb strength at low to moderate angular velocities. Whether these relationships hold at higher angular velocities is unknown and deserves further study Balance Our hypothesis that BESS scores would negatively predict SLTH distance was not supported. In fact, performance on the BESS was not significantly related to any of the tests performed. While Docherty et al 19 recently demonstrated the BESS is sensitive in detecting functional balance deficits due to functional ankle instability (FAI), the 36

44 results compared healthy subjects and subjects with FAI. The present study examined relationships within subjects in a healthy soccer population. We found no other previous studies examining the relationship between a static balance test and SLTH or other functional tests in healthy subjects. While the BESS has been found to be a valid 20 and reliable 8 clinical measure of balance, we did not find the SLTH to be related with static balance in this study. Guskiewicz and Perrin 21 defined balance as the process of maintaining center of gravity over the base of support. Subjects in the current study wore shoes for the SLTH, but not for the BESS. Balance is dependent upon interaction between the visual, vestibular, and somatosensory systems. This collective system of sensors is organized to provide feedback to the central nervous system, whereupon effector muscles coordinate activity 13 to generate supportive reactions for balance. 21 Nashner 22 reported that the somatosensory system is the primary source of proprioceptive information among healthy adults. Contact between the foot and stance surface is associated with input from mechanoreceptors like muscle spindles and Golgi tendon organs. A foam surface is specifically used to conflict the somatosensory system. 8, 21, 22 The BESS also requires subjects to close their eyes in order to eliminate visual feedback. Therefore, performance on the BESS is dependent upon continuous feedback from the somatosensory and the vestibular systems. In contrast to the BESS, the SLTH was performed with the use of athletic shoes, possibly confounding results between the two tests due to the barrier provided between 37

45 the stance surface and the foot. The SLTH also allows subjects the use of the visual system which provides feedforward and feedback control of balance. Additionally, because subjects did not hold the SLTH landing, they were not required to utilize their vestibular and somatosensory systems to maintain balance upon the body s deceleration following the final hop. The literature is unclear on this parameter. However, recent research has examined the use of a single-leg stabilization 7 maneuver to determine dynamic postural stability. 23,24 Such a task involves the continued use of somatosensory and vestibular control mechanisms throughout the completion of the SLTH landing. Future studies may examine whether holding the landing on a SLTH will be a better predictor of balance Clinical Relevance The SLTH was originally designed as a test for those recovering from injury or 14 surgery to gauge readiness for activity. 1 Throughout the literature, the SLTH is theorized 15 to require a combination of muscular strength, power and balance. 1,3,4 However, the extent to which the SLTH accurately relates to or measures deficits in any of the components has not previously been quantified. We demonstrated that the SLTH is a good predictor of lower limb muscular strength and power in a healthy soccer population. Therefore, it may be suggested that the SLTH is useful as a pre-season screening test in a coeducational NCAA Division I soccer population. Additionally, the SLTH requires minimal space, time and equipment, and may be especially helpful at youth or high school levels, where resources are limited. Future studies should examine the ability of a 38

46 SLTH to predict muscular strength and power in individuals across various sports, at different ages, and during the rehabilitation progression following injury. Additional studies should examine the relationship between SLTH and isokinetic strength tests at higher angular velocities as well as lower limb eccentric strength. The BESS is a clinically useful test to determine static balance. 8,19,20 The difference in requirements of the visual, vestibular, and somatosensory systems between the BESS and SLTH suggests that another balance test may be appropriate for comparison with a SLTH. Future studies should examine the SLTH s ability to predict performance on other balance tests Limitations Our study is not without some limitations. Because we collected data as part of a large pre-season athlete screening, we used multiple testers to obtain the measures, and could not strictly control test order. This may result in some measurement variability when the data are used for comparison at a later time. However, the same tester took all measurements on a single variable, except for the BESS, which required two examiners. In regards to the strength measures, we limited the range of motion for strength testing to 72 and only gave a brief rest interval (10 sec.) between sets. Limited range of motion may impact the peak torque, and a brief rest interval may affect peak torque on the second set. However, given that our subjects were well-trained Division I studentathletes, fatigue was not a major concern. Finally, we did not require the landing for the SLTH to be held, which may have affected the relationship with the BESS test. Recent 39

47 1 2 inquiry into balance upon completion of a dynamic task suggests that the SLTH may better predict static balance if the landing must be held Conclusions The SLTH test was originally designed to examine functional performance in a knee-injured population, and was reported to represent muscular strength, power and balance. Our study demonstrates that it is also useful in predicting lower limb strength and power in college-aged soccer athletes. Further investigation into other populations, as well as the role of postural stability in a SLTH, is warranted. 40

48 REFERENCES 1. Daniel DM, Malcolm L, Stone ML, Perth H, Morgan J, Riehl B. Quantification of knee stability and function. Contemp Orthop. 1982; 5(1): Daniel DM, Stone ML, Riehl B, Moore MR. A measurement of lower limb function: the one leg hop for distance. Am J Knee Surg. 1988; 1: Barber SD, Noyes FR, Mangine RE, McCloskey JW, Hartman W. Quantitative assessment of functional limitations in normal and anterior cruciate ligamentdeficient knees. Clin Orthop Relat Res. 1990; 255: Noyes FR, Barber SD, Mangine RE. Abnormal lower limb symmetry determined by function hop tests after anterior cruciate ligament rupture. Am J Sports Med. 1991; 19(5): Ross MD, Langford B, Whelan PJ. Test-retest reliability of 4 single-leg horizontal hop tests. J Strength Cond Res. 2002; 16(4): Ostenberg A, Roos E, Ekdahl C, Roos H. Isokinetic knee extensor strength and functional performance in healthy female soccer players. Scand J Med Sci Sports. 1998; 8: Bolgla LA, Keskula DR. Reliability of lower extremity functional performance tests. J Orthop Sports Phys Ther. 1997; 26(3): Riemann BL, Guskiewicz KM, Shields EW. Relationship between clinical and forceplate measures of postural stability. J Sport Rehabil. 1999; 8: Gustavsson A, Neeter C, Thomeé P, Silbernagel KG, Augustsson J, Thomeé R, Karlsson J. A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction [Electronic version]. Knee Surg Sports Traumatol Arthrosc. 2006; DOI /s Toumi H, Best TM, Martin A, F Guyer S, Poumarat G. Effects of eccentric phase velocity of plyometric training of the vertical jump. Intl J Sports Med. 2004; 25:

49 11. Petschnig R, Baron R, Albrecht M. The relationship between isokinetic quadriceps strength test and hop tests for distance and one-legged vertical jump test following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 1998; 28(1): Wilk KE, Romaniello WT, Soscia SM, Arrigo CA, Andrews JA. The relationship between subjective knee scores, isokinetic testing, and functional testing in the ACLreconstructed knee. J Orthop Sports Phys Ther. 1994; 20(2): Greenberger HB, Paterno MV. Relationship of knee extensor strength and hopping test performance in the assessment of lower extremity function. J Orthop Sports Phys Ther. 1995; 22(5): Pincivero DM, Lephart SM, Karunakara RG. Relation between open and closed kinematic chain assessment of knee strength and functional performance. Clin J Sport Med. 1997; 7(1): Mattacola CG, Perrin DH, Gansneder BM, Gieck JH, Saliba EN, McCue FC. Strength, functional outcome, and postural stability after anterior cruciate ligament reconstruction. J Athl Train. 2002; 37(3): Perrin DH. Isokinetic Exercise and Assessment. Champaign, IL: Human Kinetics Publishers; Kramer JF. Reliability of knee extensor and flexor torques during continuous concentric-eccentric cycles. Arch Phys med Rehabil. 1990; 71(7): Eng JJ, Kim CM, MacIntyre DL. Reliability of lower extremity strength measures in persons with chronic stroke. Arch Phys Med Rehabil. 2002; 83: Docherty CL, Valovich McLeod TC, Shultz SJ. (in press). Postural controls deficits in participants with functional ankle instability as measured by the Balance Error Scoring System. Clin J Sport Med. 20. Guskiewicz KM, Ross SE, Marshall SW. Postural stability and neuropsychological deficits after concussion in collegiate athletes. J Athl Train. 2001; 36(3): Guskiewicz KM, Perrin DH. Research and clinical applications of assessing balance. J Sport Rehabil. 1996; 5: Nashner L. Adaptation of human movement to altered environments. Trends Neurosci. 1982; 5:

50 23. Ross SE, Guskiewicz KM. Examination of static and dynamic postural stability in individuals with functionally stable and unstable ankles. Clin J Sport Med. 2004; 14(6): Wikstrom EA, Tillman MD, Borsa PA. Detection of dynamic stability deficits in subjects with functional ankle instability. Med Sci Sports Exerc. 2005; 37(2): Wikstrom EA, Powers ME, Tillman MD. Dynamic stabilization time after isokinetic and functional fatigue. J Athl Train. 2004; 39(3): Wikstrom EA, Tillman MD, Smith AN, Borsa PA. A new force-plate technology measure of dynamic postural stability: the dynamic postural postural stability index. J Athl Train. 2005; 40(4):

51 TABLES Table 1. Mean ± Standard Deviation (SD) and Value Ranges for Single-leg Triple Hop (SLTH), Vertical Jump (VJ), BESS scores, and Quadriceps (Quad 60, Quad 180 ) and Hamstring (Ham 60, Ham 180 ) Peak Torque at 60 and 180 s -1 Variable Mean ± SD Range (min-max) SLTH (cm) ± 97.0 ( ) VJ (cm) 49.3 ± 10.8 ( ) BESS (score) 13.6 ± 4.8 (5-25) Quad 60 (Nm) ± 43.0 ( ) Quad 180 (Nm) ± 31.4 ( ) Ham 60 (Nm) 92.3 ± 27.0 ( ) Ham 180 (Nm) 84.5 ± 25.4 ( ) 44

52 Table 2. Bi-variate Pearson Correlations for Single-leg Triple Hop (SLTH), Vertical Jump (VJ), Balance Error Scoring System (BESS), Quadriceps Peak Torque (Quad 60, Quad 180 ) at 60 and 180 s -1, Hamstrings Peak Torque (Ham 60, Ham 180 ) at 60 and 180 s -1 SLTH VJ BESS Quad 60 Quad 180 Ham 60 Ham 180 SLTH * * 0.767* 0.753* 0.745* VJ * 0.767* 0.753* 0.752* BESS Quad * 0.857* 0.694* Quad * 0.850* Ham * Ham *P<.01; SLTH = Single-leg triple hop, VJ = Vertical jump, BESS=Balance error scoring system, Quad 60 =Quadriceps peak torque at 60 s -1, Quad 180 =Quadriceps peak torque at 180 s -1, Ham 60 =Hamstrings peak torque at 60 s -1, Ham 180 =Hamstrings peak torque at 180 s -1 45

53 Table 3. Linear Regression: Single-leg Triple Hop (SLTH) Predicting Vertical Jump (VJ), Balance Error Scoring System (BESS), Quadriceps (Quad 60, Quad 180 ) and Hamstrings (Ham 60, Ham 180 ) Peak Torque at 60 and 180 s -1 Variable R p-value R 2 Significant F change VJ BESS Quad Quad Ham Ham Predictor: Single-leg triple hop 46

54 REFERENCES 1. Barber SD, Noyes FR, Mangine RE, McCloskey JW, Hartman W. Quantitative assessment of functional limitations in normal and anterior cruciate ligamentdeficient knees. Clin Orthop Relat Res. 1990; 255: Bolgla LA, Keskula DR. (1997). Reliability of lower extremity functional performance tests. J Orthop Sports Phys Ther. 26(3), Cote KP, Brunet ME, Gansneder BM, Shultz SJ. (2005). Effects of pronated and supinated foot postures on static and dynamic postural stability. J Athl Train. 40(1), Daniel DM, Malcolm L, Stone ML, Perth H, Morgan J, Riehl B. (1982). Quantification of knee stability and function. Contemp Orthop. 5(1), Daniel DM, Stone ML, Riehl B, Moore MR. (1988). A measurement of lower limb function: the one leg hop for distance. Am J Knee Surg. 1, Docherty CL, Valovich McLeod TC, Shultz SJ. (2006). Postural controls deficits in participants with functional ankle instability as measured by the balance error scoring system. Clin J Sport Med. 16(3), Greenberger HB, Paterno MV. (1995). Relationship of knee extensor strength and hopping test performance in the assessment of lower extremity function. J Orthop Sports Phys Ther. 22(5), Guskiewicz KM, Ross SE, Marshall SW. (2001) Postural stability and neuropsychological deficits after concussion in collegiate athletes. J Athl Train. 36(3), Guskiewicz KM, Perrin DH. (1996). Effects of orthotics on postural sway following inversion ankle sprain. J Orthop Sports Phys Ther. 23(5),

55 10. Gustavsson A, Neeter C, Thomeé P, Silbernagel KG, Augustsson J, Thomeé R, Karlsson J. (2006). A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction [Electronic version]. Knee Surg Sports Traumatol Arthrosc. DOI /s Hertel J, Gay MR, Denegar CR. (2002). Differences in postural control during singleleg stance among healthy individuals with different foot types. J Athl Train. 37(2), Horak F. (1987). Clinical measurement of postural control in adults. Phys Ther. 67(12), Markovic G, Dizdar D, Jukic I, Cardinale M. (2004). Reliability and factorial validity of squat and countermovement jump tests. J Strength Cond Res. 18(3), Mattacola CG, Perrin DH, Gansneder BM, Gieck JH, Saliba EN, McCue FC. (2002). Strength, functional outcome, and postural stability after anterior cruciate ligament reconstruction. J Athl Train. 37(3), McGuine TA, Greene JJ, Best T, Leverson G. (2000). Balance as a predictor of ankle injuries in high school basketball players. Clin J Sport Med. 10, Nashner L. Adaptation of human movement to altered environments. Trends Neurosci. 1982; 5: Nashner L. Practical biomechanics and physiology of balance. (1993). In G Jacobson, C Newman, and J Kartush (Eds.), Handbook of Balance Function and Testing (pp ). St. Louis, MO: Mosby Year Book. 18. Noyes FR, Barber SD, Mangine RE. (1991). Abnormal lower limb symmetry determined by function hop tests after anterior cruciate ligament rupture. Am J Sports Med. 19(5), Ostenberg A, Roos E, Ekdahl C, Roos H. (1998). Isokinetic knee extensor strength and functional performance in healthy female soccer players. Scand J Med Sci Sports. 8, Petschnig R, Baron R, Albrecht M. (1998). The relationship between isokinetic quadriceps strength test and hop tests for distance and one-legged vertical jump test following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 28(1), Pincivero DM, Lephart SM, Karunakara RG. (1997). Relation between open and closed kinematic chain assessment of knee strength and functional performance. Clin J Sport Med. 7(1),

56 22. Riemann BL, Guskiewicz KM, Shields EW. (1999). Relationship between clinical and forceplate measures of postural stability. J Sport Rehabil. 8, Riemann BL, Guskiewicz KM. (2000). Effects of mild head injury on postural stability as measured through clinical balance testing. J Athl Train. 35(1), Ross SE, Guskiewicz KM. (2004). Examination of static and dynamic postural stability in individuals with functionally stable and unstable ankles. Clin J Sport Med. 14(6), Ross MD, Langford B, Whelan PJ. (2002). Test-retest reliability of 4 single-leg horizontal hop tests. J Strength Cond Res. 16(4), Susco TM, Valovich McCleod TC, Gansneder BM, Shultz SJ. (2004). Balance recovers within 20 minutes after exertion as measured by the Balance Error Scoring System. J Athl Train. 39(3), Toumi H, Best TM, Martin A, F Guyer S, Poumarat G. (2004). Effects of eccentric phase velocity of plyometric training of the vertical jump. Intl J Sports Med. 25, Valovich TC, Perrin DH, Gansneder BM. (2003). Repeat administration elicits a practice effect with the Balance Error Scoring System but not with the Standardized Assessment of Concussion in high school athletes. J Athl Train. 38(1), Wikstrom EA, Powers ME, Tillman MD. (2004). Dynamic stabilization time after isokinetic and functional fatigue. J Athl Train. 39(3), Wikstrom EA, Tillman MD, Borsa PA. (2005). Detection of dynamic stability deficits in subjects with functional ankle instability. Med Sci Sports Exerc. 37(2), Wikstrom EA, Tillman MD, Smith AN, Borsa PA. (2005). A new force-plate technology measure of dynamic postural stability: the dynamic postural postural stability index. J Athl Train. 40(4), Wilk KE, Romaniello WT, Soscia SM, Arrigo CA, Andrews JA. (1994). The relationship between subjective knee scores, isokinetic testing, and functional testing in the ACL-reconstructed knee. J Orthop Sports Phys Ther. 20(2), Wilkins JC, Valovich McCleod TC, Perrin DH, Gansneder BM. (2004). Performance on the Balance Error Scoring System decreases after fatigue. J Athl Train. 39(2),

57 APPENDIX A RAW DATA Subject Age Sex Height Weight SLTH BESS VJ PTQ60 PTQ180 PTH60 PTH

58 Subject Age Sex Height Weight SLTH BESS VJ PTQ60 PTQ180 PTH60 PTH

59 APPENDIX B IRB FORM Review Process Log Applications for the Use of Human Participants in Research Principal Investigator: Complete the top section of this form only and submit it with the IRB checklist. Researcher: Original Date of Submission to Departmental Reviewer: Randy Schmitz Sandy Shultz June 10, 2005 Faculty Sponsor: N/A Projected Date of First Data Collection: August 6, 2005 Departmental Reviewer: IRB USE ONLY Date of First Receipt by Departmental Reviewer: First Review by Departmental Reviewer: Disposition by Departmental Reviewer Returned complete application to PI Requested Major Revisions Requested Minor Revisions Forwarded to ORC Date Notes Second Review by Departmental Reviewer: Disposition by Departmental Date Reviewer Returned complete application to PI Requested Major Revisions Requested Minor Revisions Forwarded to ORC Third Review by Departmental Reviewer: Notes 52

60 Disposition by Departmental Reviewer Returned complete application to PI Requested Major Revisions Requested Minor Revisions Forwarded to ORC Review by IRB Chair: Date Notes Disposition by IRB Chair Date Notes Requested Major Revisions Requested Minor Revisions Forwarded to ORC Scheduled for Full Review Review Checklist Applications for the Use of Human Participants in Research Researcher: Randy Schmitz Faculty Sponsor Submission Date: Sandy Shultz June 10, 2005 N/A Projected Date of First Data Collection: August 6, 2005 Faculty and staff members should complete this checklist before they submit an application for their own research or when they serve as the faculty sponsor for a student s research. Please submit two complete copies of the application. Review Criteria Part A is complete. Evidence of training in the protection of human participants in research is attached for all principal investigators. If the principal investigator is a student, evidence of training in the protection of human participants in research is attached for the faculty sponsor. Check by Researcher or Faculty Sponsor x x x Check by IRB Reviewer Part B: The researcher has answered questions 1-8 on separate paper. (DO NOT EXCEED THREE PAGES.) 1. Goals for the project are clearly stated and suggest the need for human participants consent. x x 53

61 Review Criteria 2. The protocol discusses: a. data gathering procedures and tools (copies of tools must be attached to the application, unless the tool is well known). Check by Researcher or Faculty Sponsor b. data recording procedures. x c. the number of participants, justification for this x number, and procedures for selecting participants. d. the length of time for procedures. x e. relationship between the researcher, participants, x and participating institutions/agencies. f. any need for deception or less than full disclosure. N/A g. if the research is conducted in class, what students N/A who are not participating will do. h. copies of letters from any agencies involved with N/A recruitment of participants or data collection. i. how consent will be obtained. x j. provisions for providing copies of consent x documents to participants. 3. The protocol describes the benefits to individual x participants AND society. 4. The protocol addresses the risks to participants, including: a. the level of risk for participants (none, minimal, x more than minimal). b. description of the risks to participants. x c. precautions taken to minimize risks to participants x d. how confidentiality will be maintained. x e. how long data will be kept x f. how data will eventually be destroyed. x 5. The protocol describes the participant population and justifies any decision to exclude persons on the basis of gender, race, or ethnicity. 6. Materials to be used in recruiting participants are attached to the protocol. 7. The CONFLICT OF INTEREST question is answered N/A, NO, or YES. (If the answer is YES, a completed Potential Conflict of Interest in Research form is attached.) x x x x x Check by IRB Reviewer 54

62 Review Criteria 8. The USE of PHI is answered NO or YES. (If the answer is YES, a completed Application to USE PHI in Research form is attached. If a waiver from the UNCG IRB is requested, a completed UNCG Request for Waiver of Authorization form is attached.) 9. The researcher has indicated that s/he will keep Confidentiality Certificates on file for all persons who assist with data collection or analysis during the research. Check by Researcher or Faculty Sponsor x Check by IRB Reviewer Part C: The Consent Form includes: 1. a clear explanation of the purpose of the research. x 2. a clear explanation of the procedures to be used. x 3. a description of the benefits to participants and/or x society. 4. the risks of participation. (If more than minimum x risk is indicated, the Consent Form includes a statement regarding compensation, availability of treatment, and directions to contact Eric Allen.) 5. the opportunity to ask questions. x 6. the opportunity to withdraw from the research x without penalty. 7. the amount of time required for participation. x 8. how confidentiality will be maintained. x 9. how long data will be kept. x 10. how data will eventually be destroyed. x 11. the researchers name and phone number for x questions about the research. 12. Eric Allen s name and phone number for x questions about the rights of human participants in research. 13. a place for the signature of a witness to the oral x presentation, when the short form is used). 14. a separate form for the assent of minors, if x applicable. Your signature indicates that you have reviewed the IRB application and believe it to be in approvable form. 55

63 Researcher s Signature Researcher s Signature IRB Initial Reviewer s Signature Date Date Date 56

64 THE UNIVERSITY OF NORTH CAROLINA GREENSBORO Instructions for Completing the Application for the Use of Human Participants in Research All research with human participants conducted by students, faculty, or staff at UNCG must be reviewed initially by a member of the University's Institutional Review Board, whether or not requests for outside funding are involved. To initiate this review, the investigator/project director must complete this application and submit it to the IRB member in his/her college/school/department. The IRB member determines the category of review appropriate for the study and forwards it to the Office of Research Compliance. The University IRB meets if full committee review is necessary. Criteria for exempt, expedited, and full committee review are available at: < Please submit the original and one copy of this human participants application at least one month prior to the date you wish to initiate data collection. (You are advised to keep a copy for your records also.) YOU MAY NOT COLLECT DATA PRIOR TO RECEIVING AN APPROVAL FORM FROM THE IRB. Faculty members will be informed by the IRB regarding the disposition of their applications and those of students they are sponsoring. Students do not receive direct notification of IRB disposition of proposals. Any changes in research protocol that affect human participants must be approved by the IRB prior to implementation unless the changes are necessary to eliminate apparent immediate hazards to the participant. Any unanticipated problems involving risks to participants or others must be promptly reported to the IRB. COMPLETE PART A (ON THIS PAGE) AND NUMBERS 1-8 ON PAGE 3. ATTACH THE APPROPRIATE CONSENT FORM INFORMATION. BE SURE TO SIGN THIS APPLICATION ON PAGE 3. Date: 06/02/2005 Part A Project Title: Normative Data for Measures of Postural Alignment, Agility, and Strength in an Athletic Population. Principal Investigator(s): Randy Schmitz PhD & Sandra J. Shultz, PhD, ATC Address of Principal Investigator: rjschmit@uncg.edu & sjshultz@uncg.edu Phone Number of Principal Investigator: (336) & (336) Address of Principal Investigator: 250 HHP Building 57

65 Relationship to the University (specify): Faculty If student, name of faculty sponsor: Faculty sponsor s addressn/a School/College: HHP Science Department: Exercise and Sport Funding Agency/Sponsor (if applicable): Projected data collection dates*: From 08/06/2005 To 08/06/2006 Have the investigators attached certificates of completion of training in the use of humans in research? Yes * Beginning date should be at least 1 month after submission of IRB application. Data collection cannot begin before IRB approval is received. 58

66 THIS PAGE IS FOR IRB USE ONLY (IRB Representative: Indicate appropriate category of review: exempt, expedited, or full review. Note: the standard requirements for informed consent apply regardless of the type of review utilized by the IRB.) Part B - Exempt This proposed research is judged to be exempt from full committee review because it falls in one or more of the following categories (see 45 CFR 46, June 18, 1991, p. 5). Check all that apply: (b)(1) (b)(4) (b)(2) (b)(5) (b)(3) (b)(6) Part C - Expedited or Full Review This proposed project has been reviewed and was found to require: Expedited Review (63 FR , November 9, 1998) Expedited category. Check all that apply: 1. (a) (b) (a) 8. (a) 2. (b) 8. (b) (c) Full IRB Review. Please explain: I certify that this project has been reviewed by me as an IRB member and that the research was not proposed by me or by a student working under my supervision. IRB Signature Date Dept. /School Print Name Send this application package to: IRB, Office of Research Compliance, 203 Foust Building. Part D - IRB Action Exempt Review (Date: / / ) 59

67 Comments: Expedited Review (Date: / / ) Full Review (Date: / / ) IRB Chairperson ORC Representative 60

68 RESPOND TO NUMBERS 1 THROUGH 8 ON SEPARATE PAPER. SUBMIT NO MORE THAN 3 PAGES FOR YOUR ANSWERS. Supporting materials (e.g. letters and consent forms) should be attached. 1. BRIEF STATEMENT OF PROJECT GOALS 2. PROTOCOL: Procedures: what will be done? How long will subjects require to complete procedures? Name and description of data gathering tool (if not well known, attach a copy) How will data be recorded? (audiotapes, videotapes, written records) Number of participants, respondents, or participants. From where will participants be obtained? What, if any, relationship exists between the researcher and the participants, and between the researcher and agencies (e.g., schools, hospitals) participating in data collection? (Example: Is researcher employed at the agency?) Any special situations (Example: Deception used because full disclosure prior to procedure would bias data.) If data collection is done in class, explain what students who do not participate will be doing. Attach statement of approval from any agencies (e.g., schools, hospitals) that will be involved with recruitment of participants or data collection. 3. BENEFITS: Describe the benefits to individual participants and to society. 4. RISKS: Describe the risks to the participants and precautions that will be taken to minimize them. This includes physical, psychological, and sociological risks. How will confidentiality of data be maintained? Attach signed confidentiality agreements (form attached) for members of research team who will have access to personal data on human research participants. Final disposition of data (What will be done with questionnaires, inventories, videotapes, and/or audiotapes? How long will they be stored, and how will they be destroyed?) How would you describe the level of risk for participants taking part in this project? No risks Minimal risks More than minimal risks 5. POPULATION: Briefly describe your participant population. Will you exclude persons on the basis of gender, race, color, or any other demographic characteristic? If so, justify. 6. PARTICIPANT CONSENT: Describe how and where participants will be informed of their rights and how informed consent will be obtained and documented. Attach a copy of consent form, oral presentation (if used), and any materials to be used in recruitment (e.g. fliers, advertisements). See next page for details on content of Consent Forms. Note: Signed consent forms must be retained in a secure location, for a minimum of three (3) years, after completion and available for IRB review. 7. CONFLICT OF INTEREST: At any time will any members of the research team or their immediate family members have financial interest in, receive personal compensation from, or hold a position in an industry sponsoring this study, or otherwise have potential conflict of interest regarding conduct of this study? N/A no industry sponsors NO YES If yes, attach Potential Conflict of Interest 61

69 in Research form. 8. PHI: Personally identifiable health information (PHI) is defined by HIPAA to include data on a person s physical or mental heath, health care, or payment for health care. As part of this study, will you obtain PHI from a hospital, health care provider, or other HIPAA-defined Covered Entity? (If unsure, read the Application to Use PHI in Research.) NO YES If yes, attach the Application to Use PHI in Research (available from ORC website.) I certify that the statements made herein are accurate and complete. I agree to inform the Board in writing of any emergent problems or proposed procedural changes. Should changes be made, I further agree not to proceed with the research until the Board has reviewed and approved the changes that I propose to make in the protocol. Principal Investigator Faculty Sponsor (for student investigators) Date Date 62

70 1. BRIEF STATEMENT OF PROJECT GOALS The purpose of the study is to establish normative, baseline data for measures of lower extremity postural alignment, agility, and strength in an athletic population. 2. PROTOCOL: Procedures and Instrumentation: Height and mass will be measured and recorded manually. Age and sex, will be subjectively reported by the subject and manually recorded by the examiner. Then 13, non-invasive lower extremity alignment variables will be measured: 1. Anterior/Posterior Pelvic Angle 2. Hamstring Extensibility 3. Thomas-Kendal test (hip flexor tightness) 4. Standing Quadriceps (Q) Angle (thigh muscle angle in standing) 5. Tibiofemoral Angle (knee angle in standing) 6. Femur (thigh) Length 7. Tibia (lower leg) Length 8. Navicular Drop (foot pronation) 9. Knee Laxity 10. Genu Recurvatum (knee hyperextension) 11. General laxity tests 12. Hip Anteversion (hip rotation) 13. Tibial Torsion (lower leg rotation) Measures 1,2,4-10,12-13 have been used in a previous approved project. Measures 3 and 11 will be added to this protocol. All measures will be recorded to the nearest degree or millimeter on protocol sheets and later in a computer database program. All standing measures will be taken with the subject in a relaxed stance, with feet placed shoulder width apart and their toes pointing forward. Each measure will be taken three times during the session. The lower extremity postural alignments will be measured using one of the following instruments: an inclinometer, a standard goniometer, a caliper, a straight ruler, or a KT 2000 Knee Arthrometer (Medmetric corporation, San Diego, CA).. Functional, agility testing will happen after the alignment testing in the following order: Single Leg Balance (BESS), Double Leg Drop Landing and Jump, Single Leg hop, T test, Agility Square, and Vertical Jump. All testing will be preceded by adequate practice time to ensure the tasks are performed correctly and safely. 1. Balance Tests (BESS) - The BESS comprises 6 conditions: double-leg, single-leg, and tandem stances on both a firm surface and foam surface. Each of the 6 conditions are performed for 20 seconds, with the number of balance errors recorded. 2. Double Leg Drop Landing and Jump- Subjects will perform 3 landings from a height of a 0.45 m (1.5 ft.) box onto the ground. When landing, subjects will be instructed to place their hands on their hips and to drop down onto the ground with both feet while immediately jumping directly up into the air and then returning to the ground. Subjects will complete 3 landings while being videotaped. 3. Single Leg Hop for distance- Subjects will stand on one leg and will perform 3 63

71 maximal hops forward with the same leg. Subjects will complete this 2 times and attempt to hop as far as possible. 4. T test for time- Subjects will sprint forward 10 yards, touch the tip of the cone, shuffle to the left 5 yards, touch a cone, shuffle to the right 10 yards, touch a cone, shuffle to the left 5 yards, touch a cone, and complete the task by backpedaling 10 yards. Subjects will complete this 2 times as fast as possible. 5. Agility Square for time - The subject sprints forward 10 yards, touches the tip of the cone, shuffles to the left 10yards, touches a cone, back-pedals 10 yards, touches the cone, and then completes the test by backpedaling 10 yards. Subjects will complete this 2 times as fast as possible. 6. Vertical Jump - Subjects will reach as high as they with one arm can to determine their standing reach. Subjects will them be instructed to jump as high as possible off both feet, reaching up as far as possible. Subjects will complete 3 jumps Strength Assessment will include bilateral Isokinetic (constant velocity) testing of the knee extensors and flexors at 60 and 180 degrees per second. Five repetitions of both flexion and extensions will occur at each testing velocity. Total time for all testing will be approximately 2 hours. Name and description of data gathering tool (if not well known, attach a copy) Instruments that will be used to take these anatomical measures include an inclinometer, a standard goniometer, a caliper, a straight ruler and ligament testing device. All of these devices are routinely used for these measures, and have been utilized in previously approved protocols. Functional and Agility testing will be measured with a stop watch or measuring tape. Strength Assessments will be performed on a Biodex System 3 Dynamometer that is routinely used for both clinical and laboratory measurement and has been utilized in previously approved protocols. How will data be recorded? (Audiotapes, videotapes, written records) Data will be obtained and maintained in electronic and written format. Demographic, non-invasive lower extremity alignment measures, and agility and strength measures recorded manually (BESS, Drop Landing, Single Leg Hop, T-Test, Agility Square, and Vertical Jump) while strength assessment measures will be collect through a computer program. Additionally all BESS and Drop landing Testing will be videotaped. All data will be reduced and entered into a computer database for storage and later analysis. All data will then be transferred to computer storage disks for later offline analyses. Data will be stored in a locked room, identified by subject code number, accessible only to the investigators. Electronic and Video data will be maintained for 2 years after all manuscripts have been published then data will be permanently destroyed. Number of subjects, respondents, or participants. 175 recreationally active and apparently healthy college aged subjects ranging in age between yrs will be recruited. Participants will include both males and females. 64

72 From where will subjects be obtained? Subjects will be recruited from the university athletic teams. (See attached flyer) What, if any, relationship exists between the researcher and the subjects? Some participants may be students in ESS department. What, if any, relationship exists between the researcher and agencies (e.g., schools, hospitals) participating in data collection? (Example: Is researcher employed at the agency? In what capacity?) N/A Any special situations (Example: Deception - Full disclosure prior to procedure is not feasible because biased data will result.) None If data collection is done in class, explain what students who do not participate will be doing. N/A Attach statement of approval from any agencies (e.g., schools, hospitals) that will be involved with recruitment of subjects/participants or data collection. N/A 3. BENEFITS: Describe the benefits to individual participants and to society. The individual will receive no direct benefit for participating in this study. This study will establish normative data for lower extremity postural alignment, agility, and strength in an athletic population.. 4. RISKS: Describe the risks to the subjects/participants and precautions that will be taken to minimize them. This includes physical, psychological, and sociological risks. How would you describe the level of risk for participants taking part in this project? No risks Minimal risks More than minimal risks There is minimal risk to participating in this study. These anatomical, agility, and strength measures are commonly used in the clinical, athletic, and research settings. There is a very small chance of muscle or joint injury during the agility and strength tests. Subjects will be given adequate practice and warm-up to help minimize these risks. In the extremely rare circumstance that a minor injury would occur, the certified athletic trainer that is assigned to the athlete s respective UNCG team will be available to care for the injury as would normally be done for any injury sustained by a UNCG athlete. How will confidentiality of data be maintained? Code numbers will be assigned to the data. The list linking the names to the code numbers will be kept in a locked file, accessible only to the investigators. Final disposition of data (What will be done with questionnaires, inventories, videotapes, and/or audiotapes? How long will they be stored, and how will they be destroyed?) Data will be stored on a PC hard drive or on video tapes in the ANRL in a locked office. Data will be retained for two years following publication of manuscripts. 65

73 How would you describe the level of risk for subjects participating in this project? No risks X Minimal risks More than minimal risks 5. Population: Briefly describe your subject population. Will you exclude persons on the basis of gender, race, color, or any other demographic characteristic? If so, justify. Current UNCG athletes ranging in age from will participate in the experiment. Subjects must be a member of a UNCG athletic team with no current history of injury to the lower extremity, or any previous history that would affect their ability to perform measures of agility and strength. Subjects will not be excluded on basis of gender, race, color, or any other demographic characteristic. 6. Subject Consent: Describe how subjects will be informed of their rights and how informed consent will be obtained and documented. Attach a copy of consent form, oral presentation (if used), and any materials to be used in recruitment (e.g. fliers, advertisements). See next pages for details on content of Consent Forms. 7. CONFLICT OF INTEREST: At any time will any members of the research team or their immediate family members have financial interest in, receive personal compensation from, or hold a position in an industry sponsoring this study, or otherwise have potential conflict of interest regarding conduct of this study? N/A no industry sponsors NO YES If yes, attach Potential Conflict of Interest in Research form. 8. PHI: Personally identifiable health information (PHI) is defined by HIPAA to include data on a person s physical or mental heath, health care, or payment for health care. As part of this study, will you obtain PHI from a hospital, health care provider, or other HIPAA-defined Covered Entity? (If unsure, read the Application to Use PHI in Research.) NO YES If yes, attach the Application to Use PHI in Research (available from ORC website.) I certify that the statements made herein are accurate and complete. I agree to inform the Board in writing of any emergent problems or proposed procedural changes. Should changes be made, I further agree not to proceed with the research until the Board has reviewed and approved the changes that I propose to make in the protocol. Principal Investigator Date Faculty Sponsor (for student investigators) Date 66

74 APPENDIX C CONSENT FORM THE UNIVERSITY OF NORTH CAROLINA GREENSBORO CONSENT TO ACT AS A HUMAN PARTICIPANT: LONG FORM Project Title: Normative Data for Measures of Postural Alignment, Agility, and Strength in an Athletic Population. Project Directors: Randy Schmitz PhD & Sandra J. Shultz PhD, ATC Participant's Name: DESCRIPTION AND EXPLANATION OF PROCEDURES: The purpose of the study is to establish normative, baseline data for measures of lower extremity postural alignment, agility, and strength in an athletic population. In order to qualify for this investigation, you must be a member of a UNCG athletic team with no current history of injury to the lower extremity, or any previous history that would affect your ability to perform measures of agility and strength. If you meet these criteria, you will be asked to attend one, 2 hour testing session. During the test session, we will record your height, weight, and age, and we will take measures of your hip, knee and foot alignment using standard measurement devices (ruler, goniometer, etc). Knee laxity (the amount of movement at the knee joint when a small force is applied to the lower leg) will also be recorded using a commercially available ligament testing device Functional, agility testing will happen after the alignment testing in the following order: Single Leg Balance (BESS), Double Leg Drop Landing and Jump, Single Leg hop, T test, Agility Square, and Vertical Jump. All testing will be preceded by adequate practice time to ensure the tasks are performed correctly and safely. 1. Balance Tests (BESS) - The BESS comprises 6 conditions: In a random order you will be asked to balance for 20 seconds using a single leg stance, double leg stance, or heel to toe stance on both a firm and foam surfaces. Each of the 6 conditions will be performed for 20 seconds. 2. Double Leg Drop Landing and Jump- You will perform 3 landings from a height of a 0.45 m (1.5 ft.) box onto the ground. When landing, you will be instructed to place your hands on your hips and to drop down onto the ground with both feet while immediately jumping directly back up into the air and then returning to the ground.. 3. Single Leg Hop - You will stand on one leg and will perform 3 maximal hops forward with the same leg. You will complete this 2 times on each the right and left leg. 4. T test - You will sprint forward 10 yards, touch the tip of the cone, shuffle to the left 5 yards, touch a cone, shuffle to the right 10 yards, touch a cone, shuffle to the left 5 yards, touch a 67

75 cone, and complete the task by backpedaling 10 yards. You will complete this 2 times as quickly as possible. 5. Agility Square - You will sprint forward 10 yards, touch the tip of the cone; shuffle to the left 10 yards, touch a cone; backpedal 10 yards, touch a cone; and then complete the test by backpedaling 10 yards. You will complete this 2 times as quickly as possible. 6. Vertical Jump - You will reach up as high as you can with one arm to determine your standing reach. You will then be instructed to jump as high as possible off both feet, reaching up as far as possible. You will complete 3 jumps Strength Assessment will include bilateral Isokinetic (constant velocity) testing of the knee extensors and flexors at 60 (slower) and 180 degrees per second (faster). You will be seated in a strength testing device and your trunk, thigh and lower leg will be affixed to the device with Velcro straps. After submaximal practice repittions you will complete five repetitions of both flexion and extension at 60 degrees per second (slower). The practice repetitions and five repetitions of both flexion and extension will them be repeated for the 180 degrees per second (faster) condition. Total time for all testing will be approximately 2 hours.. RISKS AND DISCOMFORTS: There is an extremely minimal risk of muscle or joint injury from the agility and strength testing. If at anytime the testing causes you any discomfort or concern, please notify the examiner immediately. POTENTIAL BENEFITS: There are no direct benefits to you from participating in this study. COMPENSATION/TREATMENT FOR INJURY: In the extremely rare circumstance that a minor injury would occur, the certified athletic trainer that is assigned to your UNCG team will be available to care for the injury as would normally be done for any injury sustained by a UNCG athlete. If you have a question about any injury incurred from the study please contact Mr. Eric Allen at (336) CONSENT: By signing this consent form, you agree that you understand the procedures and any risks and benefits involved in this research. You are free to refuse to participate or to withdraw your consent to participate in this research at any time without penalty or prejudice; your participation is entirely voluntary. Your privacy will be protected because you will not be identified by name as a participant in this project. The research and this consent form have been approved by the University of North Carolina at Greensboro Institutional Review Board, which insures that research involving people follows federal regulations. Questions regarding your rights as a participant in this project can be answered by calling Mr. Eric Allen at (336) Questions regarding the research itself will be answered by Randy Schmitz by calling (336) or Sandra Shultz by calling (336) Any new information that develops during the project will be provided to you if the information might affect your willingness to continue participation in the project. You will receive a copy of this consent form. 68

76 By signing this form, you are agreeing to participate in the project described to you by Randy Schmitz and/or Sandy Shultz. Participant's Signature* Date *If participant is a minor, complete the following: Participant is years old. Custodial Parent(s)/Guardian Signature(s) Signature(s) Date Custodial Parent(s)/Guardian 69

77 APPENDIX D RESEARCH CONFIDENTIALITY FORM 70